Convective Outlook Valid for Today, Tonight and Tomorrow

Regional Impacts

Today:

NL/Lab: Risk of thundershowers with small hail and strong wind gusts.

Maritimes/NL: None

Tonight:

Lab: Risk of thundershowers with small hail and strong wind gusts early this evening.

Maritimes/NL: None

Tomorrow:

NL/Lab: Risk of thundershowers with small hail and strong wind gusts.

Maritimes: None

Convective Discussion

A weak trough over eastern Newfoundland and associated cold pool aloft has triggered a few thunderstorms producing small hail this morning over the Avalon Peninsula and this may continue into the early afternoon as the trough moves eastward. Another weak trough and destabilization from surface based heating will aid in the triggering of non-severe thundershowers across western Labrador this afternoon. This feature will then move southeastward on Saturday. Daytime heating and this trough will help trigger non-severe thundershowers over southeastern Labrador and across Newfoundland tomorrow afternoon. Overall, precipitable water is low to moderate and the CAPE in realized could reach 300 J/kg and effective shear are low to moderate, but freezing levels area low, thus some stronger showers may have small hail and with somewhat inverted V profiles, locally strong wind gusts are also possible.

Thunderstorm Outlook for TODAY

 

Thunderstorm Outlook for TONIGHT

Thunderstorm Outlook for TOMORROW

 

Roberta McArthur

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NL/Labrador: A chance of non-severe thunderstorms with small hail.

NB/NS/PEI:  None.

 

Tonight

NB/NS/PEI/NL/Labrador: None

 

Friday

NL/Labrador: A chance of non-severe thunderstorms with small hail.

NB/NS/PEI: None

 

Convective Discussion

A cold pool is descending across Newfoundland and Labrador today. A few non-severe lightning strikes are possible. Additionally with the low freezing levels (3000-5000 feet) there is a chance of small hail. CAPE values are very low (300-500 J/kg) so that will limit any hail growth. Friday morning the cold pool may kick off a couple thunderstorms across the Avalon and extreme eastern Newfoundland. Friday afternoon a weak trough in associated with continued cold air across Labrador may trigger some non-severe thundershowers across western areas.  Continued low freezing levels but limited CAPE will provide the opportunity for small hail.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NL: A chance of non-severe thunderstorms extreme northeast.

NB/NS/PEI/Labrador:  None.

 

Tonight

NB/NS/PEI/NL/Labrador: None

 

Thursday

NL/Labrador: A chance of non-severe thunderstorms.

NB/NS/PEI: None

 

Convective Discussion

A cold front will move across Newfoundland this afternoon. There is a small chance of a lightning strike or two over northeastern Newfoundland before its departure. On Thursday, a cold pool will descend across Newfoundland and Labrador. A few non-severe lightning strikes are possible. Additionally with the low freezing levels (3000-5000 feet) there is a chance of very small hail. CAPE values are very low (300 J/kg) so that will limit any hail growth.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts…

 

Today

NB/NS/PEI:  A chance of severe thunderstorms bringing heavy rain, hail and strong wind gusts.

NL/Labrador: None.

 

Tonight

NB/NS/PEI/NL/Labrador: None

 

Wednesday

NB/NS/PEI/NL/Labrador: None

 

 

Convective Discussion

Low-level moisture advection continues this morning ahead of a cold front which will move across northern New Brunswick this afternoon and into southern New Brunswick this evening.  Dew point temperatures in the low 20s are occurring throughout most of the Maritimes. The combination of this warm, moist airmass and the approaching cold front should be sufficient to trigger severe weather across portions of New Brunswick, Nova Scotia and Prince Edward island this afternoon and into the evening. CAPE values of 1000-2000 J/kg and precipitable water values of up to 50 mm could produce very high rainfall rates in thunderstorms. Additionally, relatively dry mid levels and a low level jet near 30 knots will allow strong downdraft potential to exist. Effective shear of 30 to 40 knots means that some supercell storms could develop, leading to potentially damaging wind gusts. After the frontal passes tonight, quiet weather will return for a few days.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight

Thunderstorm Outlook for Tomorrow

Convective Outlook Valid for Today , Tonight and Tomorrow

Regional Impacts

NB… No impacts expected today. Some thunderstorms tonight and overnight bringing frequent lightning and possibly heavy downpours. Tomorrow… Some severe thunderstorms bringing heavy rain and potentially strong wind gusts.

PEI… No impacts expected today. Some thunderstorms overnight bringing lightning and possibly some heavier rainfall. Tomorrow… Thunderstorms possible with gusty winds and possibly heavy downpours.

NS… No impacts expected today. Some thunderstorms overnight over north areas, bringing lightning and possibly some heavier rainfall. Tomorrow… Thunderstorms possible with gusty winds and possibly heavy downpours for central and eastern regions.

NFLD… No Impacts today… Tomorrow… A chance of thunderstorms over western parts of the island tomorrow with some heavier rain possible.

Convective Discussion

For the most part, thunderstorm activity will remain upstream over Quebec and Ontario today, as a low-pressure system and its associated cold front gradually move eastward. An area of high pressure to the southwest will likely help suppress thunderstorms over the Atlantic region until the unstable airmass reaches the Maritimes tonight.

We will continue to see low-level moisture advection ahead of the approaching cold front today and overnight, with dew point temperatures likely reaching the low 20s in some areas by tomorrow. The combination of this warm, moist airmass and the surface low-pressure system will be sufficient to generate CAPE values around 2000 J/kg. With precipitable water values near 50 mm, rainfall rates in thunderstorms are likely to be very high. Additionally, strong downdraft potential exists, and it is possible that some supercell storms could develop, leading to potentially damaging wind gusts.

The timing of the cold front’s passage may prove critical; if it arrives earlier than expected, the threat of severe weather may shift somewhat eastward. Thunderstorm development over Quebec today will give us a general idea of what to expect tomorrow for New Brunswick. However, as is often the case, these systems do not always unfold as predicted, and timing may shift. Keep an eye out for alerts, not just for tomorrow but also overnight, as the system approaches.

Thunderstorm Outlook for Today

Thunderstorm Outlook for Tonight/Overnight

Thunderstorm Outlook for Tomorrow